The use of computers for Internet and other networking purposes at locations, especially private residences, served by a single analog telephone line is increasing dramatically. Many subscribers to local phone service do not find it economical or otherwise convenient to order a second line for computer use. And while times when junior is xe2x80x9csurfing the netxe2x80x9d at length and tying up the family phone may merely be occasions for family discord, there are situations where it would be appropriate for another person in the residence to be able to make a telephone call from an extension on that line, even without the assistance or cooperation of the person using the computer.
That said, there are employers who send a computer home with an employee, either for mutual convenience or for regularly scheduled work conducted from home. These circumstances can often tie up a phone line for extended periods of time. However, such sessions rarely operate at full capacity for the entire time, and there are often extended period of inactivity during a session. Since custom software is often involved, it could be arranged that upon a signal the session be suspended in a graceful manner and the telephone connection dropped for a while. During that time the phone line could be used for other calls. Then the original connection is re-established and the session resumed. There is also the technique of VoIP (Voice over IP), which allows the insertion into a session of packets of digitized voice, directed to some destination that can deal with them and perhaps send similar packets back in response. Those things being possible, there would be some interest and utility in a device that would perform the automatic sharing of the telephone line.
Finally, the computer referred to above, given that it connects to the subscriber loop with a modem, is essentially just another handset as far as other telephone equipment is concerned. What can be done to it can be done to another handset. That is, if the computer mentioned above were replaced with a regular phone, then we have alluded to a way where under definable circumstances other handsets in the same residence can have xe2x80x9cpriorityxe2x80x9d over that phone, at least for making outgoing calls at the expense of an unconditional ending of an existing call.
For many years it has been common in the construction of new homes and some commercial buildings to use station wire that has more than one pair within the sheath of a cable. For a great number of subscribers, this means that, unless an actual second subscriber line is brought to the demarcation box [holding the terminals where the line belongs to the local telephone company (telco) on the central office side and to the subscriber on the other], at least one pair inside the subscriber""s building is unused, and that it goes everywhere that there is an RJ-11 or other connector to allow an additional extension (handset or other device). Let red/green denote the pair that is connected to the central office, and yellow/black denote an unused pair, but which also appears at the modular or other style connection to the subscribers equipment. Any computer or other device that is to be interruptible by an ordinary handset (or other item of the subscriber""s equipment) is connected to red/green through a phone service re-allocation circuit that is also connected to, and that monitors, yellow/black.
Any extension or other item of phone gear that is to be able to cause such an interrupt of the equipment nominally connected to red/green is connected to yellow/black. In the case where that interrupting extension or other phone gear is normally connected to red/green via a modular jack, it may be shifted over to black/yellow via a simple adapter that plugs into that modular jack, and which itself is then plugged into. Internally, it simply routes the yellow/black (in the wall) over to the terminals normally used for red/green by a device that plugs into the adapter. An off hook condition of the interrupting equipment connected to the adapter now serves as a signal to the re-allocation circuit.
Upon being properly signaled to do so, the re-allocation circuit (gracefully or perhaps not) terminates the access of the computer or other interruptible equipment to the red/green pair, ensures that the central office ends the call, and then bridges the red/green pair to the yellow/black pair instead. This connects the extension or other equipment having priority for outgoing calls to the subscriber loop, so that an outgoing call can be made. The notion of xe2x80x9cproperly signaled to do soxe2x80x9d mentioned above can range from a simple off hook condition to the further detection of dialing a certain digit or sequence of digits (e.g., 9 or 911). In the more sophisticated cases it may be desirable for the re-allocation circuit to not only terminate the pre-existing phone call, but also supply a false dial tone to the interrupting equipment to prevent an uninformed user from thinking xe2x80x9cthe line is deadxe2x80x9d and being deflected from his purpose (dialing 911 for an emergency) as a result. In such a case the re-allocation circuit might store the dialed digits, and when real dial tone is obtained from the central office, re-dial them and then do the bridging of yellow/black to red/green.
And, of course, if the interruptible equipment is not using red/green (the on hook condition), then the re-allocation circuit automatically disconnects the central office red/green from that interruptible equipment, bridges red/green to yellow/black, and then monitors red/green from the interruptible equipment for the off hook condition. The preferred response to an off hook condition for the interruptible equipment is to wait for on hook for bridged yellow/black to red/green before undoing the bridge and proceeding with the new call for the interruptible equipment.